Field of the Disclosure
The present disclosure relates to a liquid ejection head formed by laminating a plurality of substrates.
Description of the Related Art
Inkjet printing apparatuses that eject ink to print images on a printing medium generally include a liquid ejection head that ejects ink. A known mechanism for ejecting ink with the liquid ejection head uses a pressure chamber whose capacity can be contracted by a piezoelectric element. In this mechanism, the pressure chamber is contracted due to deformation of the piezoelectric element to which a voltage is applied, so that the ink in the pressure chamber is ejected from an ejection port formed at one end of the pressure chamber. A method for manufacturing the liquid ejection head includes a method of laminating the substrates with an adhesive.
Japanese Patent Laid-Open No. 2004-358796 discloses a liquid ejection head including a channel formed substrate in which pressure generation chambers, piezoelectric elements, and electrodes are formed and a joined substrate joined to a surface of the channel formed substrate adjacent to the piezoelectric elements. The liquid ejection head disclosed in Japanese Patent Laid-Open No. 2004-358796 includes a plurality of lead-out wires each having a side connecting to a side of each piezoelectric element. Part of the lead-out wires intersect and is joined at the joined area between the joined substrate and the channel formed substrate. At the joining, the adhesive flows along the side of the lead-out wire, so that at least the side of the piezoelectric layer is covered with the adhesive.
Covering the side of the piezoelectric layer with the adhesive prevents destruction of the piezoelectric elements caused by an external environment, enhancing the voltage resistance of the piezoelectric elements. This also prevents cracking of portions of the diaphragm corresponding to corners formed by the sides of the piezoelectric elements and the diaphragm, and even if cracks are formed, the cracks can be sealed by the adhesive covering the piezoelectric elements.
However, in the method disclosed in Japanese Patent Laid-Open No. 2004-358796, it is difficult to uniformly cover the sides of the piezoelectric elements. Furthermore, the amount of the adhesive covering the piezoelectric elements tends to vary. The variation in the amount of the adhesive on the sides of the piezoelectric elements causes uneven hardness of the diaphragm, causing the driving of the piezoelectric elements to vary.